A t-way combinatorial test set is designed to detect failures that are triggered by combinations involving no more than t parameters. Assume that we have executed a t-way test set and some tests have failed. A natural question to ask is: What combinations have caused these failures? Identifying such combinations can facilitate the debugging effort, e.g., by reducing the scope of the code that needs to be inspected. In this paper, we present an approach to identifying failure-inducing combinations, i.e., combinations that have caused some tests to fail. Given a t-way test set, our approach first identifies and ranks a set of suspicious combinations, which are candidates that are likely to be failure-inducing combinations. Next, it generates a set of new tests, which can be executed to refine the ranking of suspicious combinations in the next iteration. This process can be repeated until a stopping condition is satisfied. We conducted an experiment in which our approach was applied to several benchmark programs. The experimental results show that our approach can effectively and efficiently identify failure-inducing combinations in these programs.